Social Media Monitors the Largest Fish in the Sea

The largest fish in the sea, the whale shark, is listed as vulnerable on the IUCN Red List of Threatened Species. Populations of the shark are thought to be declining, but collecting information on their whereabouts and numbers is no simple task. In addition to its physical grandiosity, the whale shark also is an epic world traveler, making it difficult to monitor. Historically, conservation biologists have monitored populations of this animal through the costly process of tagging individuals. Fortunately, scientists can get some crowdsourced help: Whale sharks, which eat zooplankton and krill, and which are not dangerous to humans, congregate for feeding in some spots that are popular among tourists. Marine biologist Tim K. Davies and his colleagues showed that photographs found on social media sites could be used to identify individual whale sharks because of the unique spots on their backs and sides. This simple technique could be used to monitor a larger number of whale sharks than was possible with previous monitoring techniques, and thus offer a much broader view of shark numbers and locations over time.